Jump to content

some help please,boost cut and low boost :)


Recommended Posts


cant see a pic mate?

 

but for the mods def needs mapping so expect thats your problem.

 

I would advise against driving it till its sorted, or at the very least keep it off boost and under 3k rpm. Can do catastrofic damage to your engine if maps wrong

Link to comment
Share on other sites

Yea but I've phoned a few subaru specialist they rekon the maps not too important atm they think it's the MAF

Just to clarify the only real mods are

3" turbo back

FMIC

Avcr

The rest is swallox unfortunately the guy must be the biggest lier that has ever walked the earth. . .

Today I've got new plugs that I'm gapping to .65

I've cleaned the maf and just letting it dry

Maybe even put in my new fuel pump

I'll see if that makes a difference

Link to comment
Share on other sites

I rekon were found the problem

3 out of the 4 coil are bust either cracked or bits missing

What's my best option now then

New coilpacks or the coilpacks convertion

post-4477-143265945384_thumb.jpg

post-4477-143265949382_thumb.jpgpost-4477-143265951371_thumb.jpgpost-4477-143265953567_thumb.jpg

The working one had this on

post-4477-143265956619_thumb.jpg

Cheers guys I feel were getting closer to fixing it

Link to comment
Share on other sites

Definitely need new coilpacks then lol

Cheapest option Buy some second hand coilpacks from a reputable breaker £20 ish (good for 330 hp ish)

or Newage coilpack with pigtails about £100 and half a day with a soldiering iron but they'll run 600hp +

Will admit i Wouldn't have thought a misfire would cause fuel cut and low peak boost just a intermittent miss at high revs on boost and sometimes a lumpy idle

Imo fuel cut is more likely to be caused by a combination of the low power map (probably made for the lower profile cams and smaller turbo ) and the decat and fmic, that are throwing the air in and gas out of the map parameters.

As tidgy said ,don't cain it about on boost to much untill it's running right, cos if it runs lean it will go bang bud [emoji6]

Link to comment
Share on other sites

Ok cheers guys

One problem tho the cut only happens when it's WOT

The car is sorn now till I can get it working properly but got acess to my dad's boost bus (Sri t zafira) :)

Ok so Savage, do you mean 100 each for the new age coils? If not I'll go for that

I belive the jdm sti did not come with a cat? And I really don't understand why a bigger exhaust will cause any problems at all its just somewere for the gasses to go

But maybe it's worth checking the O2?

I'm trying to find a standard intercooler and hoses just to fuel out this problem

I'm going fishing tomorrow to have a rest from it lol

Ok to recap

Fuel cut problem possibilities :

Fmic and exhaust not accounted for in the map.

Now looking for an original IC

Coil packs are shot.

getting new coilpacks and changed the plugs

Fuel pump shot.

Fitting my walbro soon

Maf shot

Cleaned and now drying

Ecu shot

Try a new ecu

Loom shot

Well. . .

Low boost (0.6) problem

Actuator stuck

It's now freed but it's hard to move still

Avcr not working.

Try an MBC

turbo broke.

Well. . .

Any more ideas guys?

Sorry fixed language :)

Link to comment
Share on other sites

Avcr is really just for monitoring stuff so I wouldn't have thought it would cause to many running issues.

Think I paid £80 posted for all 4 newage coil packs and the "pig tails" (the part of the newage engine loom with the coil pack plugs on ) needed for the conversion .

There's a few pics and a link on my build thread showing how to convert em .

A decat and free flowing exhaust stops back pressure which means the boost control system has to work much harder to stop the turbo spinning to much and causing over boost .

Boosting over the maps parameters can cause fuel cut if the maps boost target is exceeded. or it can mean that the turbo pushes to much air in for the maps fueling causing it to lean off and melt stuff or the ecu can chuck in to much fuel to compensate causing over fuelling which drowns the power and can cause bore wash .

Link to comment
Share on other sites

Ok sweet I get that :) BUT I don't think it's boost related as I can NOT boost past 0.6 bar I think this is my secondary problem :)

I think that a sensor is broke somewere possibly the maf? I don't think the coil packs are my main problems either all tho I have i have a working standard set as it was my cheapest option for now

From my research last night this is quite a common problem on subarus and is usually something to do with fuel grade and / or fuel delivery?

I went fishing today so I'm not working on the car and I'm busy tomorrow with family.

Is there anything you guys can suggest if I get time to do them tomorrow?

Cheers

Link to comment
Share on other sites

I tested the maf today with a multi meter and it seems to to reading but unsure as to how well

My problem is now worse as it's now cutting at a lower rpm abd the ONLY 3 things that have changed is:

1. Cleaned maf correctly with electrical contact spray and alowed to dry for a day

2. Changed new spark plugs to the correct gap and plug

3. Coilpacks were inspected and literally fell to pieces in my hand

Because of my problem getting worse and my coilpacks also I doubt this is a coincidence

And will report back when I have coilpacks fitted

Cheers

Link to comment
Share on other sites

Ok so I've installed new coil packs and a new maf and I still have the same problem :(

Ive had the dash out and put a new CEL bulb in and I get code 44

Wich is the code for the oem boost selonoid malfunction abd it's obv it's been removed any way I can bridge the plug for now?

Can this really cause a fuel cut I guess it could. . . and my best bet is to fix that fault code 1st. Just hope I'm not chasing my own tail and wasting money on it

Cheers again guys

Link to comment
Share on other sites

You could try by passing the boost control system all together and temporarily running "actuated boost"(about 0.5 bar) just see if it stops the "cut" or miss your getting

You do this by running a vac line directly from actuator to turbo outlet and pluging the vac lines you disconnected

If it improves maybe try to put the boost vac lines back to standard by picking up a 3 port boost solenoid (about £30) and re fit the standard map sensor and air density sensor (on that bracket)

As maybe the ecu is confused cos it doesn't have control over the boost the avcr has instead but not ever owning a avcr i don't know much about them tbh

Link to comment
Share on other sites

Yes please scooby ghost but the avcr is turned off atm so actuator pressure is all I'm running atm but I will try it just in case

Can an O2 sensor cause this kinda problem?

Link to comment
Share on other sites

Here's a couple of pics of the v3 set up I hacked the plugs of the cars loom in case I had to wire in a custom bit at a later date

post-1399-143309082264_thumb.jpgpost-1399-143309083414_thumb.jpg

There's a few differences in the versions but it shows how to plumb the vac lines from the map sensor to the air density sensor (bit with the burgendy "cap") and then to inlet manifold

The 3 port should be

Top port to turbo outlet

Middle port to actuator

Bottom port to intake pipe ,which is the small bore take off (blanked with a bit of blue vac line with a bolt in it) on the shiny turbo intake pipe your holding in a earlier pic .

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share




×
×
  • Create New...




Forums


News


Membership